1. Field of the Invention
The present invention relates to a propylene resin composition having excellent paintability (resistance of paint to warm water), improved injection molding properties (fluidity and the appearance of molded products) and well-balanced physical properties (rigidity and low-temperature impact strength), suitable as a material for a variety of industrial parts such as automotive parts.
2. Background Art
Reinforced propylene resin compositions compounded with talc and rubber components are excellent in molding properties, paintability and mechanical strength. Owing to these advantageous properties, they have conventionally been used as molding materials for producing a variety of industrial parts such as automotive parts, for example, bumpers, instrument panels, fan shrouds, glove boxes and garnishes, and the parts of household appliances such as television sets, video tape recorders, washing machines and vacuum sweepers.
In recent years, in line with the trend toward high-performance or large-sized automobiles, household appliances and the like, the level of requirements for the molded parts has been raised rapidly; for instance, the thinning of the molded parts has been demanded, and the propylene resin compositions have been required to be molded into complicated shapes.
To meet such requirements at higher levels, various improvements have been made on raw materials, which are polypropylene, rubber components and talc. These improvements include improvements in the properties of ethylene-propylene copolymer rubber, and reduction of particle size of talc.
However, no effective means have been proposed so far to meet requirements severer than ever, for example, to provide a resin composition which shows excellent paintability without a degreasing treatment with trichloro-ethane and has improved injection molding properties (excellent fluidity and the property of being molded into products with good appearance almost free from flow mark, sink mark and gels), and well-balanced physical properties (heat resistance and low-temperature impact strength), even when it does not contain inorganic fillers such as talc.